The present invention refers to a shoe sole comprising a front sole portion passing over into a rear sole portion via an intermediate sole portion, the top surface of the sole facing the sole of the foot being at least partially formed of the top surface of an upper sole portion consisting of wood or wood-like materials. This top surface of the sole may have an orthopaedic shape. The intermediate portion has at the top surface of the sole the support of the joint, while the rear sole portion comprises the heel.
There are already known soles consisting of an upper sole portion consisting of wood and of a lower sole portion fixed to the bottom side of the upper sole portion and consisting of an elastic material. As a rule, this lower sole portion forming the running sole is only provided at the area of the front sole portion and at the area of the heel and consists, as compared with the upper sole portion, of a thin part of rubber or polyvinyl chloride. With soles consisting of two wooden parts being connected one with the other by a flexible intermediate portion of polyurethane applied by foaming operation it is already also known to form the sole portion representing the running sole equally of polyurethane and to apply this sole portion integrally with the intermediate portion by foaming operation onto the wooden parts. With all known soles comprising an upper sole portion consisting of wood, also the rear sole portion substantially wholly consists of wood, while only the bottom side of the heel is covered by a thin running patch of elastic material. Soles comprising an upper sole portion consisting of wood have the advantage that they act in a temperature-regulating and humidity-regulating manner and support the foot in an orthopaedically correct manner if, as is known per se, the top surface of the sole is given an orthopaedic shape, i.e. is provided with a support for the inner joint, a support for the outer joint, a toe barrier or the like. However, it is a drawback of soles consisting of wood that they have no shock-absorbing properties and that walking with such soles may result in injury of the joints of the foot and the leg and of the spine, and this in particular if making sudden jumps with such soles or if the ground has an unforeseeable level difference which is not recognized by the wearer of shoes provided with such soles.
There are already also known soles consisting as a whole of an elastic synthetic plastics material acting in a shock-absorbing manner. Such soles have, however, no hygienic properties for the wearer because, for example, they are not humidity-regulating but rather promote the production of foot sweat and do not provide an orthopaedically correct support of the foot.
It is an object of the present invention to provide a shoe sole having good hygienic properties for the wearer and providing an optimum support for the foot with simultaneous preservation of the whole joint system. It is a further object of the invention to design a shoe sole such that the sole has, as least at the particularly important area of the heel, an optimum shock-absorbing property and that it reliably provides a gentle tread. It is a further object of the invention to provide a shoe sole which is highly sound-absorbing and which practically completely avoids clicking noises, which are generated when walking with wooden soles. It is a further object of the invention to provide a shoe sole, the production of which is substantially simplified. In particular, it is intended to make it unnecessary to apply a separate running sole or, respectively, a separate heel patch. It is a further object of the invention to provide a shoe sole in which the rear sole portion mainly consists of a heel applied to the upper sole portion by forming operation and preferably by foaming operation, noting that the heel can be a block heel or a wedge heel. It is a further object of the invention to provide a shoe sole with which such a heel has, in particular if its dimension as seen in normal direction of the top surface of the sole are great, the required stability and an optimum supporting property for the foot at the area of the heel. Finally, it is an object of the invention to provide a shoe sole which has a low weight and thus is easy and comfortable for the wearer. The shoe sole according to the invention shall further have a nice appearance and shape.